Structural optimization system based on trabecular bone surface adaptation

In the paper the structural optimization system based on trabecular bone surface adaptation is presented. The basis of the algorithm formulation was the phenomenon of bone adaptation to mechanical stimulation. This process, called remodeling, leads to the optimization of the trabecular network in the bone. The simulation system, as well as the finite element mesh generation, decision criteria for structural adaptation, and the finite element analysis in a parallel environment are described. The possibility of applying the system in mechanical design is discussed. Some computation results using the developed system are presented, including the comparison to the topology optimization method.     

Implementation of chemometrics in quality evaluation of food and beverages

Conventional methods for food quality evaluation based on chemical or microbiological analysis followed by traditional univariate statistics such as ANOVA are considered insufficient for some purposes. More sophisticated instrumental methods including spectroscopy and chromatography, in combination with multivariate analysis—chemometrics, can be used to determine food authenticity, identify adulterations or mislabeling and determine food safety. The purpose of this review is to present the current state of knowledge on the use of chemometric tools for evaluating quality of food products of animal and plant origin and beverages. The article describes applications of several multivariate techniques in food and beverages research, showing their role in adulteration detection, authentication, quality control, differentiation of samples and comparing their classification and prediction ability.     

Enhanced light scattering in coatings templated with interfacially stabilized colloids

Controlling inter-pore distances enables tuning the color or whiteness of microvoid coatings. While pore spacings have been modified in limited area inverse opal films, little work has occurred studying the feasibility of controlling pore spacings and thus the appearance of scalable, spray-on, microvoid inorganic coatings. In this work we investigated using interfacially stabilized colloidal templates to increase pore spacing and thus enhance Mie scattering in porous silica films. Coatings were fabricated by forming monodisperse colloids with or without a polyvinylpyrrolidone (PVP) interfacial stabilizing layer, dispersing them in a silica precursor solution, and spraying this suspension on a substrate. The films were cured and the colloids subsequently solution extracted at mild temperatures to create porous surfaces. Coatings made with PVP coated colloids had thicker pore walls and scattered light approximately 3× more efficiently than coatings made with bare colloids. Furthermore, a viewing angle dependent color shift was observed in the PVP colloid templated coatings. Side illumination of the samples with white light causes an orange appearance under angles of specular reflection, while a light blue appearance is observed out of these angles because of strong Mie scattering of short-wavelength radiation in both situations. Lastly, modeling based on Mie scattering confirms that it is the dominant optical effect in these coatings and explains the appearance of these coatings. The approach of using interfacially stabilized colloids to improve pore separation applies to many porous films and should be considered when increased light scattering is desired.     

Analysis of composite structure and primordial wood remains in petrified wood

Among all the fossils, petrified wood belongs to the most impressive and most common of materials. Still, its study has not exceeded the purely phenomenological level. The recognition of the conserved structure of petrified wood seems to be of meaning for understanding the geological past, the complete carbon cycle inside the Earth, and the structure of potential new materials. The first ever published spatial distributions of the remains of the primordial organic material (lignin, cellulose, pectins) in the cells of permineralized wood, from Dunarobba (Central Italy), are presented here. They were collected using micro-Raman spectrometry. The composite nature of the petrified material (calcite located in the lumena of cells and goethite located in the cell walls) was confirmed by electron, proton, and X-ray microprobes. The structure of the cell walls was well preserved. The mineralization process was induced by the tracheidal water flow and was stopped after formation of pipe-like goethite shielding of the cell walls on the cellulose scaffolds. The chemical (Eh and pH ranges) and probable microbial conditions for such a pattern of mineralization were determined. We estimate that substantial amounts of the primordial organic matter were preserved in bodies of petrified wood on a global scale. The wood petrifaction process, if well understood, can be a basis for the production of "everlasting" organic-inorganic composite compounds.     

Evaluation of the reject waters from co-digestion of solid wastes from agro-industries in a municipal WWTP.

Overcapacities of anaerobic digesters at municipal WWTPs are frequently used for the treatment of organic wastes in order to increase the biogas production. However, "co-digestion" of organic wastes leads to additional nitrogen loading and to additional loads of non-biodegradable COD. The effects of (co-) digestion of organic wastes from agro-industries (slaughterhouses, dairies and leather industry) on the wastewater cycle have been evaluated in full-scale investigations at Leoben WWTP with a capacity of 90,000 pe where the methane production was increased from 700 to more than 1700 Nm3 CH4 per day. For this evaluation, mass balances for COD and nitrogen have been applied to estimate the fluxes of these substances. Application of this method is described in detail. As the additional loadings, it was found that related to methane production less nitrogen is released from the organic wastes than from the waste sludge. While the ammonia nitrogen load in the effluent from sludge digestion was about 100 g NH4-N per Nm3 of CH4 produced, in the effluent from the digestion of organic wastes only 70 g NH4-N/Nm3 CH4 were found. The decrease in the COD removal efficiency after digestion of the organic wastes started was not regarded as significant enough to be seen as a consequence of the treatment of external substrate.     

Effect of dietary vitamin E supplementation on the shelf life of cured pork sausage

This study examined the shelf life of cured sausage under different packaging conditions from vitamin E supplemented pigs. One group (n=6) of crossbred pigs received a normal fattening diet containing 20 ppm α-tocopherol for 39 days before slaughter. Another group was fed a diet containing 410 ppm α-tocopherol during the same period. After slaughter, cured sausages were produced, packaged under three different atmospheric conditions, ripened for 4 weeks and then stored for 8 weeks (9?°C; 200 lux). The α-tocopherol content was recorded in the fat, liver, muscles and the sausage. TBARS, L*, a*, b* values and antioxidative capacity were evaluated in the sausage during storage. The results showed a transfer of vitamin E into tissues and sausage but no detectable effect on TBARS and colour stability. However, antioxidative effects of vitamin E were seen by provocation. Probably the effect of vitamin E in the sausage was masked by nitrite in the curing salt. The oxygen content of the packs had an influence on TBARS and colour stability.